This invention relates to the production of hydrogen gas from aluminum, water, and sodium hydroxide as catalyst, and to an apparatus for carrying out the method.
Generally speaking, it is known that under certain conditions, aluminum reacts with water to generate hydrogen and heat. It is also known, however, that this type of reaction is not sustainable at ambient temperature. It is believed that a protective oxide layer forms on a metal surface in contact with water at ambient temperature and hampers the reaction. Therefore, it has been accepted by those skilled in the art that the use of aluminum in a reaction with water to generate heat and hydrogen gas requires that the protective oxide layer is efficiently and continuously removed, and that the reaction is kept at an elevated temperature.
A number of hydrogen generators have been developed in the past. The following patent documents constitute a good inventory of the devices and methods of the prior art in the field of hydrogen gas generation using the reaction of aluminum or alloys of aluminum with water.
U.S. Pat. No. 909,536 issued on Jan. 12, 1909, and U.S. Pat. No. 934,036 issued on Sep. 14, 1909, both issued to G. F. Brindley et al. These documents disclose several compositions for generating hydrogen. The compositions comprise any metal which can form an hydroxide when it is brought into contact with a solution of a suitable hydroxide. For example, aluminum is reacted with sodium hydroxide to release hydrogen and produce sodium aluminate.
U.S. Pat. No. 2,721,789, issued on Oct. 25, 1955 to Q. C. Gill. This document discloses the structure of an hydrogen generator for reacting water with a measured dry charge of aluminum particles and flakes of sodium hydroxide. The reaction releases hydrogen gas and produces sodium aluminate.
U.S. Pat. No. 3,554,707 issued on Jan. 12, 1971 to W. A. Holmes et al. This document discloses a gas generator having bellows to raise or lower the level of water in response to the pressure inside the generator. As the level of water drops, the contact surface between the fuel cartridge and the water is lost and the reaction is terminated.
U.S. Pat. No. 3,957,483 issued on May 18, 1976 to M. Suzuki. This patent discloses a magnesium composition which produces hydrogen upon contact with water. The preferred magnesium composition comprises magnesium, and one or more metals selected from the group consisting of iron, zinc, chromium, aluminum and manganese.
U.S. Pat. No. 3,975,913 issued on Aug. 24, 1976 to D.C. Erickson. This document discloses a hydrogen generator wherein molten aluminum is reacted with water. The generator is kept at a very high temperature to keep the metal in a molten condition.
U.S. Pat. No. 4,643,166 issued on Feb. 17, 1987, and U.S. Pat. No. 4,730,601 issued on Mar. 15, 1988 both to H. D. Hubele et al. These documents disclose the structure of a fuel cell for producing heat energy and hydrogen gas. The device has a reaction chamber containing a fuel composition that is reactive with water. The fuel composition includes a main fuel part of magnesium and aluminum in a molar ratio of 1:2, and the second part is composed of lithium hydride, magnesium and aluminum in equal molar ratio.
U.S. Pat. No. 4,670,018 issued on Jun. 2, 1987, and U.S. Pat. No. 4,769,044 issued on Sep. 6, 1988, both to J. H. Cornwell. These documents describe a log made of compressed wood waste and paper. The log is coated with aluminum particles. Upon burning, the aluminum particles react with moisture in the log to emit heat due to the generation of hydrogen gas.
U.S. Pat. No. 4,752,463 issued on Jun. 21, 1988 to K. Nagira et al. This document discloses an alloy which reacts with water for producing hydrogen gas. The alloy material comprises essentially aluminum and 5 to 50% tin.
U.S. Pat. No. 5,143,047 issued on Sep. 1, 1992 to W. W. Lee. This document discloses an apparatus and a method for generating steam and hydrogen gas. In this apparatus, an aluminum or aluminum alloy powder is reacted with water to generate hydrogen gas. An electric power source is used to start the reaction. The electric power source is used to explode an aluminum conductor and to disperse pieces of molten aluminum into a mixture of water and aluminum powder. A heat exchanger is provided to extract useful heat.
U.S. Pat. No. 5,867,978 issued on Feb. 9, 1999 to M. Klanchar et al. This document discloses another hydrogen gas generator using a charge of fuel selected from the group consisting of lithium, alloys of lithium and aluminum. The charge of fuel is molten and mixed with water to generate hydrogen gas.
JP 401,208,301 issued to Mito on Aug. 22, 1989. This document discloses a process for producing hydrogen. Aluminum is reacted with water under an inactive gas or a vacuum to produce hydrogen gas.
CA 2,225,978 published on Jun. 29, 1999 by J. H. Checketts. This patent application discloses a hydrogen generation system wherein a coating on reactive pellets is selectively removed to expose the reactive material to water for producing hydrogen gas on demand. In one embodiment, aluminum and sodium hydroxide are reacted with water to release hydrogen gas and produce sodium aluminate.
Various other processes to produce hydrogen gas have been described in the art, as reacting water with magnesium, sodium, potassium, lithium, calcium, iron, zinc or steel.
Although the hydrogen production processes of the prior art deserve undeniable merits, it is believed that the catalytic reaction of aluminum and water, using sodium hydroxide as the catalyst, to release hydrogen gas from water at room temperature has never been anticipated or observed and disclosed by prior inventors. It is also believed that the prior art is short of suggestion with regards to a hydrogen production process which can be improvised in a home workshop using common materials and equipment, to generate heat and light during a power outage for example.
Concerning hydrogen generators, the prior art discloses a number of hydrogen generators for use with fuel cells or as heat sources for thermal engines for examples. These generators are believed to be complicated and precarious to operate by untrained individuals. These hydrogen generators are believed to be designed for use by scientists and other professionals working under laboratory conditions.
As such, it will be appreciated that there continues to be a need for a production process and for an apparatus for generating hydrogen gas and heat using a simple reaction which can be started at room temperature and carried out safely by ordinary persons not having a formal education in chemistry and chemical processes.
Broadly stated, the process for producing hydrogen gas according to the present invention consists of reacting aluminum with water in the presence of sodium hydroxide as a catalyst. This process is advantageous for being carried out at room temperature and for producing large quantities of heat and hydrogen gas at high purity.
In accordance with another feature of the present invention, there is provided a process for producing heat, light and hydrogen gas. The process comprises the steps of providing an expandable receptacle; partly filling the expandable receptacle with water and introducing an aluminum element and a catalyst in the water. The process also comprises the steps of partly sealing the expandable receptacle and reacting the aluminum element with the water. Then, the expandable receptacle is expanded and contracted in response to more or less pressure therein, and by the same action, the fuel element is emerged out or immersed into the water. This method is advantageous for providing the ability to control the intensity of the reaction between the water and the aluminum element in response to the pressure generated inside the expandable receptacle by the reaction.
In another aspect of the present invention, the aluminum element comprises a coiled strip of aluminum having several layers set vertically in the water. As hydrogen gas is generated between the layers of the coiled strip of aluminum, the hydrogen gas raising to the top of the water causes a partial vacuum between the layers of the coiled strip, to absorb more water through the bottom of the coiled strip, thereby promoting an effective wetting of the aluminum element.
In yet another aspect of the present invention, there is provided an apparatus for producing heat, light and hydrogen gas. The apparatus comprises essentially an expandable receptacle having an upper end, a central portion and a fuel element suspended to the upper end and inside the central portion. The apparatus also has means for raising and lowering the fuel element in the central portion in response to more or less pressure inside the expandable receptacle, respectively.
The apparatus according to the present invention uses the pressure and temperature of a reaction occurring between a fuel element and the water contained therein to control the degree of immersion of a fuel element in the water and consequently to control the intensity and duration of the reaction between the fuel element and the water.
In yet a further feature of the present invention, the apparatus comprises a timer mechanism and latch means responsive to the timer mechanism for timely raising the fuel element out of the water contained in the receptacle.
The processes and apparatus according to the present invention are practical and safe for use by the general public to generate heat, light and hydrogen gas in power outage situations for example, or in remote locations where electricity is not available. Furthermore, the method and apparatus according to the present invention use aluminum waste readily available in domestic garbage and metal working shops, to promote recycling and energy conservation.
In accordance with yet another aspect of the present invention, there is provided a process for producing alumina, comprising the step of reacting aluminum with water in the presence of a catalyst wherein the catalyst is sodium hydroxide. This process is advantageous for extracting available energy from a reaction between aluminum waste and water, and for simultaneously producing a basic material which can be reused for manufacturing new aluminum.
Although, the utility of the processes and apparatus of the present invention can be appreciated by the general public, it is also believed that the processes and apparatus of the present invention will find advantageous applications in other more scientific fields, such as the fields of fuel cells, internal combustion engines, thermal engines, heating systems and lighting appliances.
Other advantages and novel features of the present invention will become apparent from the following detailed description of the preferred embodiment.